The deal adds to the 141,000-square-foot deal that Mizuho signed in June, bringing its planned footprint to a total of 411,000 square feet. The company is expected to start occupying the 2.1-million-square-foot building between West 50th and 51st Streets in 2019.

Mizuho plans to relocate employees from 320 Park Avenue, 1440 Broadway and 125 West 50th Street, as Commercial Observer previously reported. Rockefeller did not disclose the terms of the new transaction. The asking rent in the previous deal was in the low $80s per square foot, as CO reported.

“The growth of Mizuho Americas has been tremendous,” John Buchanan, head of strategy for Mizuho Americas, said in a statement. “We are reaching capacity at our existing leases and look forward to consolidating our many offices throughout the city in one, world-class location that affords us the ability to continue implementing our expansion plans.”

Rockefeller Group is currently completing a Pei Cobb Freed & Partners-designed $600 million redevelopment of the 48-story 1271 Avenue of the Americas. The renovation includes a new glass curtain wall facade that will allow 60 percent more daylight into offices and restoration of the lobby. Part of the reason that Mizuho Americas chose to expand planned offices is because of the redevelopment, according to Guiltinan, a senior vice president at Rockefeller Group.

“This commitment… demonstrates the market’s positive reception to the ongoing renovations to this iconic asset,” Guiltinan said in prepared remarks. “1271 Avenue of the Americas provides a rare opportunity to relocate to virtually new construction in the heart of Midtown.”

A spokeswoman for CBRE declined to comment and a spokeswoman for Savills Studley did not immediately respond to an inquiry for comment.